Slue Foot Sue originated in the stories of the American Tall Tales, but first debuted in Jack of Fables as an unwitting ally of the Bookburner.
Major Story Arcs
When we are first introduced to the Bookburner, we learn that he can utterly destroy a Fable and remove it from the cultural mindset by burning the original version of the book they starred in, leaving them a ghostly figure that is beholden to him. Bookburner threatens Natty Bumppo into working for him by showing him a copy of the Leatherstocking Tales. It is unknown whether or not such coercion was used on Sue, but the next time we see Bumppo, Sue is accompanying him. The two set out on the trail of Jack Horner and his friends in the Homeland Americana and quickly catch up with them. In an act of sacrifice, Paul Bunyan throws himself on the pursuers once Jack promises to take care of Babe.
The diversion works but the group then spends many months on the run from the trackers. Eventually the skills of Sue and Bumppo prevail and they capture Hillary Page and Humpty Dumpty. It is unknown what happened to the pair after their successful capture and delivery of the prisoners. They are not seen in the Bookburner's army as it storms the Golden Boughs. If they were among the ranks, then they were probably destroyed when the facility exploded.